Can you use a multi-resource card to build two different items? The rules seem to imply that you build one feature, pay for it, then if you would like, build another. And since you don't get change, if you only use one of the two items on the card, you cannot use it for the next thing you build. This means that once the two obelisks and the 2 pieces of the throne are built, the multi-resource cards become entirely pointless. Any clarification? Thanks

Actually, you buy everything you want first before you build any of it. So yes, you may use a multi-resource card for different items in the same shopping trip. You only "lose" your change once you are completley done buying items for that round.

While the resource count paid during a visit to the Quarry never has to be exact (e.g. a "tainted" 2- Marble Slabs resource may be used where a single Marble Slab would suffice), and can be split over several pieces being built at the same time (e.g. a 2-Wooden Logs resource may be used to account for the Wooden Log portion of a Column wall and of a Door frame), change is never given back. Any unused portion of a Resource card played during the turn is lost.